Selenium (Se) is an essential element for humans but is not considered as essential for plants. However, its beneficial role in improving plant growth and stress tolerances is well established. In order to study the role of Se in lead (Pb) toxicity in Faba bean (Vicia faba L.).This experiment was carried out on plants grown for 2 weeks on Hoagland medium supplied with 50 μM Pb in the form of lead nitrate Pb(NO3)2 and/or Se concentrations of 1.5 and 6 μM in the form of sodium selenite Na2SeO3 with three replications. The result showed that Pb decreased chlorophyll “a” and chlorophyll “b”. However, supplementation of Se restores the negative effect of Pb and increases pigment content. Osmolytes (soluble sugar and proline) were increased under Pb stress and further increase was observed with addition of Se. Pb also increased production of lipid peroxidation and the activities of antioxidant enzymes such as catalase and ascorbate peroxidase. Supplementation of Se decreased accumulation of lipid peroxidation and increased the activities of antioxidant enzymes to greater levels in roots and shoots.
The data suggest that Se might have an important protective effect in plants under Pb and may help to alleviate the adverse effect of Pb on the growth of Vicia faba L.